The amount of data generated and collected by businesses has seen exponential growth in recent years, with such growth expected to continue into the future. Data is the underlying resource on which business computing processes are based. To ensure that business processes deliver the expected results, they must have access to the data. Management and protection of business data is vital for the availability of business processes. Management covers aspects such as configuration, performance, and protection, which ranges from what to do if media fails, to complete disaster recovery procedures.
In a mainframe environment, the management of storage is centralized. Storage devices are connected to the mainframe host, and managed directly by the IT department where a system programmer (storage administrator) is completely dedicated to this task. It is relatively straightforward and easy to manage storage in this manner.
The advent of client/server computing created a new set of problems, such as escalating management costs for the desktop, as well as new storage management problems. The information that was centralized in a mainframe environment is now dispersed across one or more networks and is often poorly managed and controlled. Storage devices are dispersed and connected to individual machines; capacity increases must be planned machine by machine; storage acquired for one operating system platform often cannot be used on other platforms.
The computing industry has recognized for decades the split between presentation, processing, and data storage. Client/server architecture is based on this three-tiered model. The top tier uses the desktop for data presentation. The desktop is usually based on Personal Computers (PC). The middle tier, comprising application servers, does the processing. Application servers such as e-mail or web servers are accessed by the desktop and use data stored on the bottom tier, which comprises storage devices containing the data.
To address the foregoing problems, technologies related to Storage Area Network and Server Area Network (both referred to herein as a “SAN”) networking and storage solutions have been and are being developed. A SAN is a high-speed network that allows the establishment of direct connections between storage devices and processors (servers) within the distance supported by the networks connection infrastructure, which most commonly comprises Fibre Channel (FC) infrastructure. In today's SAN environments, the storage devices in the bottom tier are centralized and interconnected, which represents, in effect, a move back to the central storage model of the host or mainframe.
The SAN can be viewed as an extension to the storage bus concept, which enables storage devices and servers to be interconnected using similar elements as in local area networks (LANs) and wide area networks (WANs): routers, hubs, switches, directors, and gateways. A SAN can be shared between servers and/or dedicated to one server. It can support both homogeneous (i.e., common platform) and heterogeneous (mixed platform) architectures.
An example of a pair of heterogeneous SAN architectures 100A and 100B is shown in FIG. 1. Each architecture is configured in accordance with the conventional three-tier architecture discussed above, including a client tier, an application server tier, and a storage tier. The client tiers include various types of client computers 102, such as workstations, personal computers, laptops, etc. Client computers in a client tier are connected to servers 104 in application server tier via a LAN (local area network) or WAN (wide area network) 106 (labeled 106A and 106B for the respective architectures 100A and 100B). In turn, the servers 104 in a server tier are connected to storage devices 108 in the storage tier via respective SANs 110A and 110B.
A heterogeneous architecture supports various server hardware and platform types, and is independent of platform vendor and operating system type. Storage devices 108 in the storage tier 106 are used to store data that may be accessed via SANs 110A and 110B. In general, most any type of mass storage device may be deployed in a SAN storage tier if that device is compatible with the SAN infrastructure.
The consolidation of business entities into larger enterprises has led to a common occurrence where individual SANs, representing islands of storage, are isolated from one another. In order to facilitate continuous communication between different SANs, an efficient transport mechanism must be employed. Under one conventional scheme, the transport mechanism is done using Ethernet interfaces and switches with an IP (Internet Protocol) such as shown in FIG. 1. In order to interface between SAN 110A and SAN 110B, SAN gateways 112A and 112B are used between IP network 114. The SAN gateways facilitate reconfiguration of data according to specific protocols to facilitate the exchange of data across the gateway.
While SANs are generally considered highly efficient networks, the traffic sent over a SAN is much different than the traffic for which IP networks were designed to handle. IP networks are predicated on routing, and typically serve large numbers of customers and may include hundreds or even thousands of routers, switches, bridges, etc. Under the IP protocol, data is sent by encapsulating the data into relatively small packets that include headers that are examined at each routing hop along the route between a data source and data destination, such as between SANS 110A and 110B of FIG. 1. This encompasses a large amount of overhead. In contrast, SAN traffic typically comprises larger payloads sent across very short routes, often point-to-point. Thus, SANs are designed for handling bulk traffic, with routing considerations being secondary. When sending data between SANs using an IP network, these large payloads must be broken into many packets of much smaller size at a source SAN gateway, sent across the IP network individually, often along different routes, and reassembled at a destination SAN gateway. As a result, data transmissions via SANs using conventional transport mechanisms such as IP networks is very inefficient and consumes valuable bandwidth and network resources.